Create a new DateTime object corresponding to
the specified Civil Date and hour h,
minute min, second s.

The 24-hour clock is used. Negative values of h,
min, and sec are treating as counting backwards
from the end of the next larger unit (e.g. a min of -2 is
treated as 58). No wraparound is performed. If an invalid time portion is
specified, an ArgumentError is raised.

of is the offset from UTC as a fraction of a day (defaults to
0). sg specifies the Day of Calendar Reform.

y defaults to -4712, m to 1, and d
to 1; this is Julian Day Number day 0. The time values default to 0.

Create a new DateTime object corresponding to
the specified Commercial Date and hour
h, minute min, second s.

The 24-hour clock is used. Negative values of h,
min, and sec are treating as counting backwards
from the end of the next larger unit (e.g. a min of -2 is
treated as 58). No wraparound is performed. If an invalid time portion is
specified, an ArgumentError is raised.

of is the offset from UTC as a fraction of a day (defaults to
0). sg specifies the Day of Calendar Reform.

y defaults to 1582, w to 41, and d
to 5; this is the Day of Calendar Reform for Italy and the Catholic
countries. The time values default to 0.

Create a new DateTime object corresponding to
the specified Julian Day Number jd and hour h,
minute min, second s.

The 24-hour clock is used. Negative values of h,
min, and sec are treating as counting backwards
from the end of the next larger unit (e.g. a min of -2 is
treated as 58). No wraparound is performed. If an invalid time portion is
specified, an ArgumentError is raised.

of is the offset from UTC as a fraction of a day (defaults to
0). sg specifies the Day of Calendar Reform.

Create a new DateTime object corresponding to
the specified Ordinal Date and hour h,
minute min, second s.

The 24-hour clock is used. Negative values of h,
min, and sec are treating as counting backwards
from the end of the next larger unit (e.g. a min of -2 is
treated as 58). No wraparound is performed. If an invalid time portion is
specified, an ArgumentError is raised.

of is the offset from UTC as a fraction of a day (defaults to
0). sg specifies the Day of Calendar Reform.

y defaults to -4712, and d to 1; this is Julian
Day Number day 0. The time values default to 0.

Create a new DateTime object by parsing from a
String, without specifying the format.

str is a String holding a date-time representation.
comp specifies whether to interpret 2-digit years as 19XX
(>= 69) or 20XX (< 69); the default is not to. The method will
attempt to parse a date-time from the String using various heuristics; see
#_parse in date/format.rb for more details. If parsing fails, an
ArgumentError will be raised.

The default str is ‘-4712-01-01T00:00:00+00:00’; this is
Julian Day Number day 0.